This invention relates to an apparatus employing an assembly of four flat vanes for obtaining kinetic energy from a working fluid, and more particularly, to a simple, few moveable parts apparatus employing an assembly of four flat vanes presenting a varied frontal area for engaging a working fluid.
Heretofore devices for extracting kinetic energy from such working fluids as the wind have made use of impeller-driven generators, which are mounted on derricks. These devices, often referred to as windmills, have a rudder means or directional vane for directing the impeller into the eye of the wind. The derrick must support the weight of the impeller-driven generator, the forces associated with the wind, and the gyroscopic forces normally associated with impeller-driven generators. The impeller may require close-tolerance vanes. In addition, some impellers may have means for adjusting the angle of attack or cyclic pitch change of the vanes to extract kinetic energy from a low velocity wind and reduce the rotational speed of the impeller in a high velocity wind to prevent destructive gyroscopic forces.
Another distinct type of device for extracting kinetic energy from a working fluid consists of vanes which rotate about a vertical axis. These vertical mounted devices, such as the Tice rotor, Savonius rotor, S-rotor, and Darrieus rotor, do not always employ close-tolerance vanes, are omnidirectional to the wind in a horizontal plane, do not necessarily require dericks, are not subject to some of the destructive gyroscopic actions normally associated with impeller-driven generators, and operate at lower rotational speeds. In addition, these vertical mounted devices may have means to adjust the angle of attack and cyclic pitch change of the vanes. This is usually done with gears or mechanical-electro means in conjunction with a directional vane to determine the eye of the wind. These devices, which include anemometers, rotate when the working fluid drag on one side of the vertical axis of rotation exceeds the working fluid drag on the other side.